This invention relates to an electrical connector and more particularly to a multi component electrical connector assembly adapted to be connected in a lap joint relationship to coil ends of adjacent electrical coils in a dynamoelectric machine rotor to connect a plurality of coils in electrical series relationship. Reference is made to U.S. Pat. No. 3,292,025--Victor 12/13/66 assigned to the same assignee as the present invention, and incorporated by reference herein.
In a dynamoelectric machine a plurality of rotor windings such as the field winding for a large turbogenerator comprise electrical coils which are wound in a narrow rectangular loop configuration having longer side sections and shorter end sections. The coils may be wound from a continuous electrical conductor to comprise a plurality of superimposed narrow rectangular conductor loops in registry relationship in a stacked array.
A turbogenerator rotor is usually of a cylindrical configuration having narrow axial slots formed in its periphery in spaced circumferential relationship. The narrow rectangular electrical coils as above described are placed in the rotor slots so that each opposite longer side section of the coil loop reside in one of a pair of the predetermined spaced axial slots. In the stacked array of conductor loops or turns, the end of the first conductor at the start of the coil may be at the bottom of the stacked array of conductors and the other end point of the coil is at the top of the stack. In some instances, i.e. with respect to very large dynamoelectric machines the individual coil conductor or strand may comprise one or more rectangular cross section copper strips of a total thickness approaching 0.75 inch and a width of about 1.75 inches. The stack height of a plural loop coil as described may be about 6.0 inches and accordingly the coil groove depth exceeds this dimension by an amount sufficient to accommodate electrical insulation between the conductor strands, and insulation and coil wedges at the top of the slot.
In the usual practice of winding coils for dynamoelectric machines the coils are wound in what is referred to as right hand or left hand winding so that in the stacked array of a pair of adjacent right and left hand coils, the starting point of one coil is at the same elevation as the end point of the oppositely wound adjacent coil. Also, the coils or loops are wound so that the distance between the longer sides of the narrow rectangular loop is generally equal to the distance on the circumference of the rotor between the axial slots into which the longer sides are positioned. The beginning and end of a coil are found in the shorter end sections of the narrow rectangular coil and those shorter end sections including a beginning or end point are referred to as half straps. The coils for the rotor are dimensioned so that, in their assembled relationship in the slots in the rotor, the first coil in the series for example lies within the second coil i.e., the first coil is a smaller and narrower rectangular coil lying generally concentrically within a larger second coil i.e. the rectangular configuration of the second coil is longer and wider than those counterpart dimensions of the first coil, and the longer sides of the second coil fit in a pair of more widely spaced slots in the rotor than those of the first coil. In this relationship the shorter end sections of each coil lie adjacent to each other with a half strap of each coil also lying closely adjacent to each other, and because of the opposite winding of the coils, one of the adjacent half straps represents the end of one coil while the adjacent half strap represents the beginning point of another and adjacent coil.
As described, in a series of coils, the second as well as the subsequent coils to be assembled to the rotor, are larger than the preceding coil and surround preceding coils in coaxial relationship so that the longer side sections of the subsequent coils fit in axial slots which are peripherally spaced from the preceding coil sides. A large number of coils on the rotor results in a significantly great number of end section conductors at the ends of the rotor leading to what is referred to as a very congested space at the rotor ends between the slots. Furthermore, as noted herein and in the Victor patent, adjacent coils of a series of coaxial coils are oppositely wound so that, in one slot, the coil may be described as wound from the bottom to the top of the slot and the subsequent coil is wound from the top to the bottom of the slot with the result that the end of the last conductor of one coil is at the same radial height from the axial center line of the rotor as the beginning end of an adjacent coil. Ordinarily, all coils in the rotor are to be electrically connected in electrical series relationship and an electrical bridging connector or member is utilized at the periphery or top of a pair of coils to connect the ends of two adjacent half straps which are generally at the same radial height. A further connector is utilized at the bottom of the stacked array of a pair of adjacent coils to connect adjacent half strap ends. This procedure is continued for the series of coils so that the end of one coil is connected to the beginning of an adjacent coil for electrical series connection of all coils in the series. As further described in the Victor patent, because of the large number of coil turns, and the large cross-sectional dimensions of the conductors, there is limited space at the rotor ends for electrical bridging connectors. When the coil ends to be connected are at the top of the stacked array of conductors in a pair of adjacent coils an electrical bridging connector may comprise a simple strip conductor brazed to the coil ends. However, at the bottom of the stacked array, due to various electrical and mechanical design problems, the coil ends may not lie in the same plane and therefore be radially offset from each other. Accordingly, a coil connector at the bottom of adjacent coils comprises a more complex configuration with attendant higher production costs.